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Smilodon - Also known as the saber-toothed tiger, this species lived during the Pleistocene epoch. According to the site Newdinosaurs, the feline lived between 2.5 and 10 million years ago.

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Smilodon - The giant cat is believed to have emerged in North America and gone extinct in South America. It is similar to a leopard in appearance and is marked by its giant canine teeth.

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Mammoth - According to Newdinosaurs, the woolly mammoth went extinct "just" 4,500 years ago and inhabited cooler regions of the planet. Fossils were found in countries in Europe, northern Asia (specifically Siberia), and North America.

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Mammoth - These animals, similar to modern-day elephants, lived up until the last Ice Age and served as food for humans living in the Neolithic period.

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Livyatan melvillei - This species is similar to a whale and is yet another mysterious animal that inhabited the planet millions of years ago.

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Livyatan melvillei - According to Newdinosaurs, it lived approximately 13 million years ago, during the Miocene epoch. Fossils were discovered in 2008, in Peru.

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Canis Dirus - The Dire wolf lived during the Pleistocene epoch and is believed to have gone extinct 10 thousand years ago, according to the site Prehistoric.

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Canis Dirus - Although it is related to the gray wolf and dog, the animal is not actually an ancestor of either of these species. 

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Gigantopithecus - This extinct animal lived on the planet between six million and 200,000 years ago, according to Newdinosaurs. It is believed to have lived in the current regions of China, India, and Vietnam.

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Megatherium - This animal was a giant sloth living during the Miocene and Pleistocene epochs, between 10 million and 10,000 years ago, according to Newdinosaurs.

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Megatherium - This was a herbivore that lived in what we consider North America. The animal measured on average four meters in height and weighed several tons.

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Doedicurus clavicaudatus - This animal was a prehistoric glyptodont that lived in the Pleistocene epoch and up until the last Ice Age, 11,000 years ago.

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Doedicurus clavicaudatus - This animal looks like a mix between a tortoise and armadillo, given its shell. Fossils were found on the American continent, more specifically in Argentina.

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Camelops - The ancestor of the camel lived from the Pliocene epoch up until the end of the Pleistocene epoch (from 3.6 million years ago until 11,700 years ago), according to Britannica.

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Camelops - It had long and robust legs, a long neck, and one hump, making it similar to modern-day dromedaries. It is believed that the animal went extinct in North America.

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Procoptodon - A type of marsupial similar to the modern-day kangaroo lived in Australia during the Pleistocene epoch, according to Newdinosaurs. It was a herbivore, measuring 4.9 m in height and weighing around 200 kg.

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Hipparion - The ancestor of the horse lived between around 20 million to two million years ago and lived on almost all continents, according to Newdinosaurs.

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Purgatorius - This animal, similar to a rat, was a prehistoric mammal that lived approximately 65 million years ago, according to the site Newdinosaurs.

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Purgatorius - It lived in modern-day North America, was omnivorous, and lived in trees (similar to primates).

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Glyptodon - This mammal is known as the ancestor to the armadillo and lived in North America. According to an article published on Wilder, it is believed that these giants emerged around 35 million years ago.

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Titanoboa cerrejonensis - This species of snake lived on Earth millions of years ago, after the dinosaurs went extinct. Scientists estimate that the giant snake measured up to 14 m in length.

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Entelodon - The animal is also known as the "pig from hell," probably due to its ferocious appearance.

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Entelodon - This prehistoric animal appears to be an ancestor of the pig and lived in the plains of Eurasia until the end of the Eocene epoch (around 30 million years ago).

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Daeodon - This giant Artiodactyla, also a subspecies of Enteledon, had an appearance similar to a mixture of a dog, boar, and ox.

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Daeodon - According to Newdinosaurs, the animal lived during the Miocene epoch and was discovered by Edward Drinker Cope in 1878, who gave it its name. They are also sometimes referred to as "hell pigs."

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Thylacinus cynocephalus - This extinct animal, also known as the Tasmanian tiger or Tasmanian wolf, was the largest carnivorous marsupial of modern times, according to the site Prehistoric.

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Thylacinus cynocephalus - Native to continental Australia, Tasmania, and New Guinea, it is believed that this animal went extinct in the 20th century.

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Paraceratherium - The animal is also called a rhinoceros-giraffe and is one of the largest terrestrial mammals that has ever existed.

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Paraceratherium -

According to Newsdinosaurs, the prehistoric species lived between around 33 million years ago to 23 million years ago, during the Oligocene epoch.

See also: Chimeras, hybrids, and genetically modified animals

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